But it doesn't work this way. You don't work strictly with the language itself, you work with the whole ecosystem. Libraries, tools, snippets, SO questions, etc. And many of those are still in 2.7 or at least need to specify different solutions for 2.7... It is still a pain.
Admittedly there were some libraries that took a long time to switch, but at this point there is no serious library left, that did not make the switch.
Python 3.6+ or burn it to the ground